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From: David Laight <David.Laight@ACULAB.COM>
To: 'Christoph Hellwig' <hch@lst.de>,
	"x86@kernel.org" <x86@kernel.org>, "Jan Kara" <jack@suse.com>
Cc: "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-api@vger.kernel.org" <linux-api@vger.kernel.org>,
	"linux-arch@vger.kernel.org" <linux-arch@vger.kernel.org>,
	Jan Kara <jack@suse.cz>
Subject: RE: [PATCH 3/3] quota: simplify the quotactl compat handling
Date: Fri, 7 Aug 2020 09:38:38 +0000
Message-ID: <f894de9f065f4bf9a451668dfbf35591@AcuMS.aculab.com> (raw)
In-Reply-To: <20200731122202.213333-4-hch@lst.de>

From: Christoph Hellwig
> Sent: 31 July 2020 13:22
> 
> Fold the misaligned u64 workarounds into the main quotactl flow instead
> of implementing a separate compat syscall handler.
> 
...
> +static int compat_copy_fs_quota_stat(struct compat_fs_quota_stat __user *to,
> +		struct fs_quota_stat *from)
> +{
> +	if (put_user(from->qs_version, &to->qs_version) ||
> +	    put_user(from->qs_flags, &to->qs_flags) ||
> +	    put_user(from->qs_pad, &to->qs_pad) ||
> +	    compat_copy_fs_qfilestat(&to->qs_uquota, &from->qs_uquota) ||
> +	    compat_copy_fs_qfilestat(&to->qs_gquota, &from->qs_gquota) ||
> +	    put_user(from->qs_incoredqs, &to->qs_incoredqs) ||
> +	    put_user(from->qs_btimelimit, &to->qs_btimelimit) ||
> +	    put_user(from->qs_itimelimit, &to->qs_itimelimit) ||
> +	    put_user(from->qs_rtbtimelimit, &to->qs_rtbtimelimit) ||
> +	    put_user(from->qs_bwarnlimit, &to->qs_bwarnlimit) ||
> +	    put_user(from->qs_iwarnlimit, &to->qs_iwarnlimit))
> +		return -EFAULT;
> +	return 0;
> +}

That might look better as a 'noinline' function that copied
all the fields into an on-stack struct compat_fs_quota_stat
and then did a single copy_to_user().

(I do 'like' qs_pad - I wonder what the person who added
it was smoking.)

	David

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Registered Address Lakeside, Bramley Road, Mount Farm, Milton Keynes, MK1 1PT, UK
Registration No: 1397386 (Wales)


  parent reply index

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-07-31 12:21 improve compat handling for the i386 u64 alignment quirk v2 Christoph Hellwig
2020-07-31 12:22 ` [PATCH 1/3] compat: lift compat_s64 and compat_u64 to <asm-generic/compat.h> Christoph Hellwig
2020-07-31 12:22 ` [PATCH 2/3] compat: add a compat_need_64bit_alignment_fixup() helper Christoph Hellwig
2020-07-31 12:22 ` [PATCH 3/3] quota: simplify the quotactl compat handling Christoph Hellwig
2020-08-07  9:07   ` David Laight
2020-08-07  9:38   ` David Laight [this message]
2020-08-06 13:50 ` improve compat handling for the i386 u64 alignment quirk v2 Ingo Molnar
2020-09-17  7:41 improve compat handling for the i386 u64 alignment quirk v3 Christoph Hellwig
2020-09-17  7:41 ` [PATCH 3/3] quota: simplify the quotactl compat handling Christoph Hellwig

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